Aerobic exercise is a popular form of exercise that improves one's cardiovascular health by reducing blood pressure and providing other benefits to the human body. Aerobic exercise generally involves low intensity physical exertion over a long duration of time. Typically, the human body can adequately supply enough oxygen to meet the body's demands at the intensity levels involved with aerobic exercise. Popular forms of aerobic exercise include running, jogging, swimming, and cycling among other types of aerobic exercise. In contrast, anaerobic exercise often involves high intensity exercises over a short duration of time. Popular forms of aerobic exercise include strength training and short distance running.
Many choose to perform aerobic exercises indoors, such as in a gym or their home. Often, a user will use an aerobic exercise machine to have an aerobic workout indoors. One such type of aerobic exercise machine is an elliptical, which often includes foot supports that move in reciprocating directions when moved by the feet of a user. Often, the foot supports will be mechanically linked to arm levers that can be held by the user during the workout. The arm levers and foot supports move together and collectively provide resistance against the user's motion during the user's workout. Other popular exercise machines that allow a user to perform aerobic exercises indoors include treadmills, rowing machines, stepper machines, and stationary bikes to name a few.
One type of elliptical exercise machine is disclosed in U.S. Pat. No. 8,025,610 issued to Yao-jen Chang. In this reference, a safety device for use with an elliptical exercise machine includes a holder frame, a movable member, a locking member, and an operating member. The holder frame is fixedly mounted in the elliptical exercise machine at a predetermined selected location. The movable member is movably mounted in the elliptical exercise machine. The locking member is movably mounted in the holder frame in order to selectively lock the movable member from moving. The operating member is operable to move the locking member. A user can lock the movable member of the elliptical exercise machine after each exercise. When the user uses the elliptical exercise machine again and steps on the pedals of the elliptical exercise machine before starting to exercise, the user will not accidentally fall from the elliptical exercise machine due to an unexpected displacement of the center of gravity. Other types of elliptical exercise machines are described in U.S. Pat. No. 5,031,901 issued to Sulevi Saarinen and WIPO Patent Publication No. WO/2008/138124 to Robert Dickie. Each of these references is herein incorporated by reference for all that they contain.